Four years after COVID, misinformation still endangers some Americans' health. Here's why.

Jesse Ehrenfeld, an anesthesiologist at a Wisconsin hospital, asked a patient about to have heart surgery if she would consent to a blood transfusion should it become necessary.

It's a standard question. But the patient refused.

It was 2021, and the COVID-19 vaccine had become publicly available only a few months earlier. This patient, though, made it clear she did not want it – or blood from anyone who already had it.

"It was at that moment I knew we were in for it," Ehrenfeld said.

More: Unsure how to tell medical fact from fiction? You're not alone. Experts offer some tips.

It was four years ago this week that the scope of the crisis facing the world began to crystallize: The World Health Organization classified COVID-19 as a pandemic, and then-President Donald Trump declared a nationwide emergency that would last three years.

Though the pandemic no longer dominates headlines as it once did, misinformation about nearly every aspect still spreads online. More than 1.1 million people in the U.S. have died of COVID-19, including hundreds of thousands who, for reasons often rooted in misinformation, chose not to get vaccinated. About 30% of the population hasn't received the initial series of vaccines.

The spread of COVID-19 misinformation on social media has been a concern for public health experts since the start of the pandemic. Nearly 25% of all claims debunked by USA TODAY's fact-checking team from March 2020 to December 2021 were related to COVID-19. That fell to about 10% from January 2022 to December 2023.

The specific claims varied, but common themes included the existence and origin of the disease, purported alternative treatments and all manner of claims about the vaccine.

Fact check: No evidence COVID-19 vaccine 'shuts off' the heart, contrary to anti-Kelce post

Ehrenfeld said he and other doctors continue to have conversations with patients who believe misleading or outright false claims about COVID-19, sometimes to the detriment of their health. Thousands of people across the country are still hospitalized with the disease every week, and some never make it out.

"It's heartbreaking," said Ehrenfeld, who last year became president of the American Medical Association. "We work so hard to practice evidence-based medicine."

Experts told USA TODAY that misinformation about COVID-19 eroded trust in public health agencies, heightened already inflamed political divisions and created a near-constant challenge to discern fact from fiction.

"We're more willing to believe that dark forces are working behind the scenes against us," said Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia. "That's what these kinds of conspiracy theories provide."

Rebuilding trust, finding empathy for people swayed by misinformation

Medical providers said their focus now is finding ways to have respectful conversations with patients regardless of their perspective.

"(Frustration) doesn't get us anywhere," said Amanda Johnson, a New York City primary care doctor. "I think those conversations are more likely to go poorly if you take it as a personal affront."

She has talked about misinformation with patients, some of whom have even asked her to review social media posts they've seen. The most animated responses come from patients who believe they're losing control or having something forced on them, said Johnson, who also leads NYC Health + Hospitals' AfterCare program for New Yorkers recovering from COVID-19 or living with long COVID.

Many people are disparaging or dismissive when talking about people who believe misinformation, but it can happen to anyone, said Sedona Chinn, an assistant professor in the life sciences communication department at the University of Wisconsin-Madison.

"I never admit that I'm wrong when somebody backs me into a corner and yells at me. You're just going to get more defensive," Chinn said. "People have good intentions in trying to correct misinformation. But it's a challenging thing to do. It's a challenging thing to admit that you were deceived."

Ehrenfeld said he asks his patients questions to learn what they believe, why they believe it and where they heard it. It doesn't happen often, but he has "seen the lightbulb go off" for some patients, including some who have agreed to be vaccinated after talking with him. Most people, Ehrenfeld said, still have a level of trust in their doctor.

"While that trust has eroded a little bit, there is still tremendous value and opportunity in these personal one-on-one relationships," he said.

Doctors have consistently been the most trusted source for health information during the pandemic, said Liz Hamel, director of public opinion and survey research at KFF, a healthy policy research firm.

The organization's polling shows more than 90% of people trust their doctor's health recommendations "at least a fair amount." Only about two-thirds had the same level of trust in federal agencies like the Centers for Disease Control and Prevention and the Food and Drug Administration.

The work of rebuilding trust in the medical community has only just begun.

"We have to continue to elevate credible messages," Ehrenfeld said. "We have to make it easy for people to obtain accurate, correct information."

The development of a safe and effective vaccine against COVID-19 was the "greatest scientific or medical achievement in my lifetime," said Offit, who lived through the development of the polio vaccine.

But the spread of misinformation about the COVID-19 vaccine has lowered trust in other vaccines, risking outbreaks of diseases – measles, for instance – once thought all but eradicated. If that continues it could, in the long run, be the "horrific" legacy of this pandemic, he said.

"If we start to take down school vaccine mandates, you'll start to see these diseases come back," Offit said. "Maybe that's going to be the legacy of this pandemic. I hope not, but that's the scariest part."

Health misinformation, anti-vaccine sentiment predate the pandemic

The pandemic amplified mistrust in the medical establishment that existed long before COVID-19.

In 1982, a television documentary called "DPT: Vaccine Roulette" aired nationally featuring children with severe health problems purportedly caused by the vaccine for pertussis, or whooping cough.

Medical experts denounced it as "imbalanced" and "inaccurate." The American Academy of Pediatrics said the documentary's "distortion and total lack of balance of scientific fact" caused "extraordinary anguish and perhaps irreparable harm to the health and welfare of the nation's children."

The documentary – which Offit called the birth of the anti-vaccine movement – led to a wave of lawsuits against vaccine manufacturers that eventually prompted lawmakers to pass the National Childhood Vaccine Injury Act. That created a program to compensate people for injuries caused by vaccines and protects manufacturers from litigation.

Fact check: No, CDC data doesn't show 99% of reported COVID-19 deaths were from other causes

Peter Hotez, a vaccine researcher and dean of the National School of Tropical Medicine at Baylor College of Medicine, became familiar with health misinformation after his now-adult daughter was diagnosed with autism. Hotez took on those who blamed vaccines, publishing a book in 2018 titled, "Vaccines Did Not Cause Rachel's Autism: My Journey as a Vaccine Scientist, Pediatrician, and Autism Dad."

Hotez showed that, in his daughter's case, a rare genetic mutation caused repetitive behaviors and communication problems. The claim that vaccines are somehow linked to autism has been repeatedly debunked by multiple studies.

Vaccines weren't as political then as they became during the pandemic, Hotez said.

"It was mostly groups monetizing the internet, selling phony autism cures, nutritional supplements and anti-vaccine conspiracy books," he said.

That mirrors what Tara Kirk Sell, a senior researcher at the Johns Hopkins Center for Health Security, found studying health misinformation that spread during the Ebola outbreak in West Africa. The outbreak started in 2014 and, over about two years, killed 11,325 people.

Sell said she expected to find misinformation about the event itself – and did – but was surprised by the way it was also used as a "vehicle for all of these other goals."

"If you want to increase political division, if you want to promote a social policy, if you want some sort of financial advantage, the health event and health-related misinformation is what gets in front of people's eyes," she said.

The threat posed by health misinformation was a focus of Event 201, a tabletop pandemic training exercise conducted by the Johns Hopkins Center for Health Security, the World Economic Forum and the Bill and Melinda Gates Foundation. The mock drill led to several recommendations, including that governments and the private sector find ways to fight misinformation before the next pandemic.

The training exercise took place in October 2019, less than two months before the first cases of COVID-19 were reported.

Even then, the stakes were clear: "It's really going to mess up the response," Sell recalled thinking about potential misinformation. "It's going to put responders in danger. It's going to make it so people don't trust the government."

COVID-19 misinformation left many in the 'muddled middle'

The pandemic created a perfect storm for misinformation.

The rapid pace of scientific research made it hard for some people to keep up, which created opportunities for misinformation to spread, Hamel said.

The isolation early on made people more reliant on social media and other online communities, Chinn said. More people were searching for reliable information because the situation was so uncertain.

"Those emotions, like anxiety and fear, lead us to want to try to find some more information," she said. The emotional intensity also led people to act and share info online "without critically evaluating the information."

A KFF survey released in August 2023 found most adults in the U.S. have encountered health misinformation – and many aren't certain what to believe.

Asked to evaluate several false claims about COVID-19 and vaccines, about a third of respondents thought the false claim that COVID-19 vaccines have caused thousands of sudden deaths in otherwise healthy people is either definitely or probably true.

"Black adults are more likely to believe this false statement than white adults, while Republicans and independents are more likely than Democrats to do so," the report says. "People with college degrees are less likely than those with a high-school education or less to say this is true."

Fewer respondents thought other false claims about COVID-19 were definitely or probably true, including that ivermectin is an effective treatment for the disease, that more people have died from the vaccines than from the virus, and that the vaccines cause infertility.

Most people, however, are in what the report called the "muddled middle."

"These are people who, when you ask them about a false claim, they say it's either probably true or probably false," Hamel said. "That's really the first indication of how confusing it can be for the public to decipher the information they're coming across."

Fact check: Post exaggerates global deaths, then blames them on the COVID vaccine

Adding to the confusion is the question of what sources of information to trust.

A 2023 study looking at the phrase "Do your own research" found the phrase, though technically a call to dig deeper, was instead often associated with "anti-expert attitudes and mistrust, leading to inaccurate beliefs," the study says.

"What we found was people who had positive views about 'doing your own research' were more likely to become more misinformed about COVID over time," said Chinn, one of the study's authors.

'Political allegiance' influenced willingness to believe misinformation

By the time the COVID-19 vaccines became available in late 2020, nearly 300,000 people in the U.S. had died of the disease. But it didn't affect all groups equally, illustrating the deadly toll misinformation can exact.

Offit, who called the vaccine a "ticket out of the pandemic," said he would have thought early on that such a vaccine, given the dire circumstances, might ultimately lead to the demise of anti-vaccine groups.

Instead, the opposite has happened. Some prominent anti-vaccine groups have seen massive funding increases since the pandemic began.

"This was their chance to misinform the public about vaccines," Offit said.

Fact check: Recipients of FDA-approved COVID-19 vaccines can donate blood immediately

The vaccine has been perhaps the most frequent target of misinformation during the pandemic. It has been wrongly blamed for "sudden deaths" and "turbo cancer," among other things. There have also been false claims about its development, safety and effectiveness.

But attitudes toward the vaccine – and the willingness to believe false claims about it – have been distinctly divided along political lines.

KFF polling shows Republicans were more likely than Democrats to say they believed false claims about the COVID-19 vaccine and other vaccines were true. KFF also reported that only about a quarter of Republicans planned to get the latest COVID-19 vaccine compared with nearly three-quarters of Democrats, "reflecting patterns seen throughout the COVID-19 pandemic."

In a study out of Cornell published in October 2020, researchers analyzed millions of news articles published that year and found the "single largest driver" of COVID-19 misinformation at the time was one person: then-president Trump, a Republican. It notes the largest spike in misinformation coverage – at almost 18,000 articles – happened April 24, 2020, when Trump baselessly suggested bleach and other disinfectants might be a possible treatment for COVID-19.

And COVID-19 has accordingly taken a disproportionate toll.

A 2023 study by Yale researchers found excess deaths during the pandemic were more than 40% higher among Republicans than Democrats in the two states it examined, Ohio and Florida. A 2022 study published in Health Affairs found similar results.

Hotez said the hundreds of thousands of people in the U.S. who died after being convinced not to get vaccinated are victims of a "predatory movement."

"They went down that rabbit hole as a form of political allegiance and paid for it with their lives."

This article originally appeared on USA TODAY: How COVID-19 misinformation is still hurting some Americans' health